- Kernel Sceduler Behavior (Tempolary) 
Mr. Matsubara, Igel 

* Story in the past presentations
 Have been investigating behavior of RT tasks snd non-RT tasks.
 The goal is to implement device drivers in user land.

* Today's presentation
 Actually implemented a device driver in user land.
 Will report it.

* Current status in embedded development
  More development of new device drivers
  Development in user land would be easier.

* For embedded, user space device driver may be practical
- Benefit
 Use of tools/libraries
 Ease of development and debugging
 Less system hang ups
 
- Then, what features necessary for device drivers?
 Access to I/O memory
 Interrupt receipt and handling
 Allocation of and access to physical memory

* In user process, general threads and device processing threads can share memory area and cooperate

* Investigation of performance of user space device drivers
  It turned out that user space device drivers are sometimes faster, depending on conditions.
  No problem for handling synchronous interrupt.
  Otherwise, it might be difficult.

* Q&A
- Throughput was reported in the presenation. How about latency?

  To be measured.

- Try signal?

 Although the report was blocking I/O, how would it be with non-blocking I/O?
 For example, waking up with signals?

- Comment
  Want to know up to how much K will it be transferrable with this serial transfer without dropping data.


